Ultrasound Detected Myokymia Is Associated with Increased Duration of Hospitalization and Healthcare Cost After Rattlesnake Bite in Arizona

Neurotoxic envenomation by rattlesnakes has been of great concern throughout the Americas and in Arizona. In addition to clinical weakness, patients sometimes display myokymia, a disordered fasciculation of skeletal muscle, which is mediated by Mojave toxin. As neurotoxic venoms have been associated with increased release of creatine kinase (CK) activity and concordant increases in length of stay (LOS) in the hospital, it was retrospectively determined if point-of-care ultrasound detected myokymia at the bite site was associated with increased CK activity, LOS, and healthcare cost compared to rattlesnake envenomations not associated with myokymia. The Arizona Poison and Drug Information Center patient database was queried for patients with point-of-care ultrasound exam results at or near the bite site from 2017 to 2021. Using point-of-care ultrasound to detect subclinical myokymia, thirty-seven patients that met inclusion criteria were determined to have myokymia (n = 16) and/or not display it (n = 21). Patients with myokymia had twice the CK activities, double the LOS, and two-fold the healthcare costs of patients without myokymia detected. These findings serve as a rationale for future investigations to link ultrasound detected myokymia with patient outcomes.